The objectives of this proposal are to investigate the problems associated with microvascular replantation of traumatically amputated extremities. We will investigate methods to: prolong viability prior to replantation; quantitate microvascular blood flow; prevent vasospasm; develop proper microvascular grafting techniques for arterial and venous losses, evaluate present instrumentation methods, and develop alternative procedures and investigate the regenerative capacity of free muscle transfers. The significance of this research relates to a better understanding of tissue injury and improved final functional capacity of patients with severely injured extremities.